Substrate holders are generally used to perform technological operations in the field of microelectronics notably for substrates whose diameter is smaller than the diameter of standard substrates (i.e. than substrates whose dimensions allow the handling and conducting of technological operations in currently available standard equipment). Therefore these substrates of non-standard size can nevertheless be treated using conventional devices designed for the performing of technological operations on standard substrates. For example with a 200/300 substrate holder, it is possible to obtain the depositing of a layer of dielectric material on silicon substrates 200 mm in diameter whilst using a depositing device designed for substrates 300 mm in diameter.
Yet the substrate holders used in layer depositing devices have a limited lifetime. Over and above a threshold thickness of layers accumulated on the holder, the quantity of accumulated material is likely to cause changes in standard depositing conditions or in subsequent deposition properties. For example, for a substrate holder in silicon, when the stack of SiO2 layers deposited on the holder has a thickness above a threshold thickness the stack of SiO2 peels off. This leads to the formation of particles which pollute the deposition of a further SiO2 layer on a substrate. The presence of a large amount of SiO2 on the holder may also lead to a capacitance possibly modifying the plasma forming conditions required for the depositing of a further SiO2 layer. It is then necessary to remove the stack of layers formed on the substrate holder in order to recycle this holder and to be able to make re-use thereof for further depositing steps.
For this purpose, it is possible to perform chemical etching of the stack of layers deposited on the holder. For example, for a stack of SiO2 layers, efficient use can be made of a hydrofluoric acid solution (HF). However, some deposited materials are not attacked by currently existing chemical etching solutions or they have a slow etching rate which entails very lengthy recycling treatment. In addition when the successive deposits form stacks of various materials, it is difficult to find a single chemical solution capable of removing all the deposited layers. The sequencing of several treatments in several chemical solutions is too time-consuming to be envisaged.
In addition, it is also possible to use mechanical grinding to remove the stack of layers deposited on the holder. However, some substrate holders may have a geometry making the use of grinding impossible. This is particularly the case with substrate holders whose receiving surface has a ring of peripheral material. In this case, it is difficult to carry out mechanical grinding without modifying the dimensions of the ring or the thickness of the substrate holder.